• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.87-94
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• 1992

Film boiling heat transfer characteristics in liquid-liquid systems are studied experimentally. Liquid gallium as a heating liquid, n-pentane, freon-113, and ethanol are used as boiling liquids. In gallium-n-pentane and gallium-freon-113 systems the minimum film boiling point occurred at higher temperature than those observed in copper-boiling liquid systems. However MFB point occurred almost at the same temperature for the case of ethanol. This difference are due to the effects of contact angle and interfacial agitations in gallium-boiling liquid systems. Film boiling heat transfer rate, for the gallium-boiling liquid systems considered in this work, found to be approximately 10% higher than those in copper-boiling liquid systems, whose main cause is believed to be gallium-boiling liquid interfacial agitations affected by the density ratio between gallium and boiling liquid.

• Journal of Biosystems Engineering
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• v.27 no.4
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• pp.327-334
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• 2002

In this study, energy conversion from thermal energy to mechanical power by using n-pentane was tested and exergy variation, cycle number, water quantity pumped and thermal efficiency were analyzed. The energy conversion was done and the water head could be ten meters on the experimental conditions. The operating temperature range of cycle was recommended to be around the liquid-vapour saturation temperature of the working fluid on the viewpoint of the maximum work. The cycle diagram was analyzed by the exergy analysis. For the constant water head, the cycle number was decreased and the water quantity per day was increased and thermal efficiency become higher when the water quantity per cycle become increasing. For the constant pumping water quantity per cycle, cycle number and the water quantity per day was decreased and the thermal efficiency become higher because the saturation temperature become higher when the water head become higher.

• Korean Journal of Hazardous Materials
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• v.6 no.2
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• pp.39-46
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• 2018

최근 전자제품 생산업체에서 EPS를 직접생산하게 되면서 EPS 공정이 증가하고 있다. EPS에는 펜탄이 포함되어 있으며, 펜탄은 하이브리드 혼합물로 구분할 수 있어 높은 화재폭발의 위험성을 가지고 있다. 각 공정별 펜탄의 누출률은 발포기, 사일로실, 저장실 순이나 발포기의 경우 일반적으로 밀폐되어 있으므로 사일로 실이 가장 화재폭발 위험성이 높다고 판단하였다. 사일로실의 누출률 중 70%는 사일로 상단을 통해 누출되며, 사일로 상단을 통해 누출되는 펜탄의 거동을 분석하여 사일로실 위험성 완화대책을 수립하였다. 1. 폭발위험구역 2종으로 관리, 2. 사일로상단 50cm이내 환기설비 설치 또는 Push-Pull 구조의 환기설비설치, 3. 사일로 하단 1.4m이내에 가스감지기 설치, 4. 60%이상의 습도유지

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E3
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• pp.101-107
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• 2001

Source profiles were developed for a total of 45 volatile organic compounds (VOC) that can be emitted from gasoline evaporation. The gasoline samples of five major brands (for each season) were blended on the basis of the market share in Seoul area and analyzed by a GC-MS/FID system. In addition, we calculated gasoline evaporative compositions using the Raoult's law from the liquid gasoline compositions. The measured and estimated gasoline vapor compositions agree well each other. As a group, alkanes are the most abundant in the gasoline vapors profiles (77.4% on average), followed by alkenes (19.1%), and aromatics (1.7%). As a specie in gasoline vapor, i-pentane is the most abundant, followed by n-butane, n-pentane, i-butane, trans-and cis-2-butenes, 2-methyl-2-butene, and trans-and cis-2-pentenes . It was also seen that aromatic content was much lower in the vapor phase compositions. From the comparison between experimental and calculated compositions, we identified the fact that once the gasoline vapor composition is reliably constructed entirely from the measured gasoline composition and the Raoult's law calculations, the need for doing separate chemical analyses of the gasoline vapor can be reduced.

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.147-152
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• 2010

Poor fruit set during winter period is one of the biggest problem in plastic tunnel watermelon cultivation. Hand pollination is inevitable to maximize fruit set of the winter watermelon. Productivity and viability of pollen grain and organic solvents for pollen storage were investigated. All cultivars produced more than 10 mg/flower except for 'Kumchun' cultivar. Pollen amount per flower were 13.8 mg in 'Bok' and 12.1 mg in 'Speedkul'. Germination rate of pollen grains incubated at $30^{\circ}C$ right after soaking in pentane solvent were 76% in 'Kumchun' as the lowest and 92% in 'Apollokul' as the highest. The pollen of 'Bok' showed the highest germination rate by 75% after a 15-day storage in pentane. All cultivars showed their pollen germination rate below 25% after a 24-day storage. Among the cuitivars, speed of pollen tube growth in vitro were relatively lower in 'Kumchun' and 'Sambokkul' by below $50\;{\mu}m/hr$. Pollen tube of these cultivars tended to burst during its elongation on the medium. Pollen stored 24 hrs in organic solvents showed 45, 39, 34, 23, and 19% of germination in pentane, ethyl ether, n-hexane, ethyl acetate, and acetone, respectively. Compared with light condition, pollen viability was higher in darkness during pollen storage in organic solvents. Pollen grain was susceptible to the organic solvent. The viability of pollen grains seems to be influenced greatly by duration of soaking pollen in organic solvent and the polarity of solvents. Organic solvent damages surface of pollen grain and extent of damage was varied by the solvents.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2004.10a
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• pp.444-449
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• 2004

• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.478-484
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• 1997

In a recent paper[Bull. Kor. Chem. Soc. 17, 735 (1996)] we reported results of molecular dynamic (MD) simulations for the thermodynamic and structural properties of liquid n-alkanes, from n-butane to n-heptadecane, using three different models. Two of the three classes of models are collapsed atomic models while the third class is an atomistically detailed model. In the present paper we present results of MD simulations for the dynamic properties of liquid n-alkanes using the same models. The agreement of two self-diffusion coefficients of liquid n-alkanes calculated from the mean square displacements (MSD) via the Einstein equation and the velocity auto-correlation (VAC) functions via the Green-Kubo relation is excellent. The viscosities of n-butane to n-nonane calculated from the stress auto-correlation (SAC) functions and the thermal conductivities of n-pentane to n-decane calculated from the heat-flux auto-correlation (HFAC) functions via the Green-Kubo relations are smaller than the experimental values by approximately a factor of 2 and 4, respectively.

• Membrane Journal
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• v.10 no.1
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• pp.19-29
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• 2000

To estimatc mutual diffusion coefficient for the analysis of mass transfer phenomena in polymer/solvent system, two models are proposed and the equations are derived. The estimates of mutual diffusion coefficients are obtained by two models suggested in this work and compared with and experimental data and Vrentas-Duda's. Vrentas-Duda's self diffusion coefficient was used for the mutual diffusion coefficient. Derivative of chemical potential on solvent was derived and used using original UNIFAC-FV and modified UNIFAC-FV. However, Vrentas-Duda's equation for mutual diffusion coefficient contains Flory-Huggins parameter x. For the derivative of chemical potential term, Vrentas-Duda assumed that parameter x was constant and independent of temperatures and concentrations The assumption is one of shortcoming in vrentas-Duda's mutual diffusion coefficient. New methods proposed in this work do not have such assumptions and simplifications. For the solvent of cyclohexane, n-pentane, and n-hexane in PIB(polyisolbutylene) and PMS-BR (poly(p-methylstyrene-co-isobutylene), new methods well correlate the experimental data at various temperatures and concentrations, and predicted the experimental data much better than Vrentas-Duda's for the PIB/toluene system. It is shown that new methods are excellent tools for correlating mutual diffusion coefficient data in polymer/solvent system over wide ranges of temperature and concentration without any assumptions or simplifications.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.459-468
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• 2002

Literature data measured by the author have been processed to report on the effect of solute structure on gas liquid partition coefficients of eleven normal, branched and cyclic alkanes ranging in carbon number from five to nine in sixty nine low molecular weight liquids. The alkane solutes are n-pentane(p), n-hexane(hx), n-heptane(hp), n-octane(o), n-nonane(n), 2-methylpentane(mp), 2,5-dimethylpentane(dp), 2,5-dimethylhexane(dh), 2,3,4-trimethylpentane(tp), cyclohexane(ch), and ethylcyclohexane(ec). The solvent set encompasses most of those studied by Rohrschneider as well as three homologous series of solvents (n-alkanes, 1-alcohols and 1-nitriles) and several perfluorinated alkanes and highly fluorinated alcohols. An excellent linear relationship was observed between lnK and the carbon number of n-alkanes. The effective carbon numbers of branched and cyclic alkanes were determined in a similar fashion to the method of Kovats index. We found that the logarithm of solute vapor pressure multiplied by solute molar volume was a perfect descriptor for the linear relationship with the median effective carbon number.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.577-580
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• 2007

분자 크기가 너무 커 가스 하이드레이트를 형성하지 않는다고 알려진 n-펜탄과 n-헥산이 다른 구조-H 형성 화합물과 혼합되어 사용될 경우 구조-H 동공 내에 함께 포접되는 것으로 확인되었다. 구조-H 하이드레이트의 형성 및 미세구조 분석은 고체 NMR 및 X-선 회절 분광법을 이용하여 확인하였다. 이러한 혼합 화합물에서 보이는 구조-H 하이드레이트 형성은 전체적인 구조-H 형성 화합물에서 나타나는 일반적 특징인 것으로 여겨진다.